Question

Which of the given statement(s) about synthetic oligonucleotides is/are correct?

• A. Chemical synthesis extends the DNA chain from 3´→5´end
• B. They can be utilized for site-directed mutagenesis
• C. Chemical synthesis extends the DNA chain from 5´→3´end
• D. They can be utilized as radiolabeled probes

Answer 1

The Correct Option is A, B, D

To address the question of which statements regarding synthetic oligonucleotides are correct, we evaluate each given option based on established biological and chemical principles:

1. Chemical synthesis extends the DNA chain from 3´→5´end: DNA synthesis in the lab typically extends from the 3' to 5' end direction. This method involves adding nucleotides sequentially to the 3' hydroxyl group, supporting the accuracy of this statement.
2. They can be utilized for site-directed mutagenesis: Synthetic oligonucleotides can be employed to introduce specific mutations at particular sites within a gene sequence. This process, known as site-directed mutagenesis, is a critical tool in molecular biology for studying gene function. Therefore, this statement is correct.
3. Chemical synthesis extends the DNA chain from 5´→3´end: In contrast to the option stated above, this statement is incorrect because chemical DNA synthesis in the laboratory setting proceeds from 3' to 5', not 5' to 3'. Thus, this option does not hold true under standard laboratory practices.
4. They can be utilized as radiolabeled probes: Synthetic oligonucleotides can indeed be labeled with radioactive isotopes to serve as probes for detecting specific DNA or RNA sequences. This application is especially relevant in techniques such as Southern blotting or in situ hybridization. Hence, this statement is correct.

Based on the explanations provided, the statements that are correct are:

• Chemical synthesis extends the DNA chain from 3´→5´end
• They can be utilized for site-directed mutagenesis
• They can be utilized as radiolabeled probes

Therefore, the correct answer reflects options one, two, and four.